Low fps caused by limited mainthread

please notice your RAM usage. You should recheck your windows virtual memory settings ( at least overall 32Gig memory is necessary… so set MAX at least to 20gig ). But also then is a “file” on SSD not real memory.

Then… this topic exist soooooooooo often within this forum ( search ) . I cant count it.
Also the part that “one core is in higher load” ( and mostly the latest ). If I remember me, I mentioned this somewhere too…

A good starting point for you might be:

But you should have allways in mind that at some airports you get just 20fps ( e.g. LFPG ) …
and additional have mods again a partly huge impact on the “fps” ( just use the forums search function ).